A roll stand having features in common with the present invention is described in U.S. Pat. No. 5,035,131 not constitute a prior publication. U.S. Pat. No. 5,035,131, in the same way as the present application, is based on the problem of compensating for the relatively short working life of the rolling segments, which are subjected to very heavy mechanical loads during operation, by minimizing the shutdown times required for the replacement of the rolling segments. In the prior art, this replacement is effected by arranging a plurality, preferably four or eight rolling segments, in the support member. If the rolling segment is worn, a new rolling segment can be brought into working position by the turning of the entire support member, after it has been removed to a position outside of the stand. This requires loosening the strips which guide the chocks, which support the support member in the housing, and handling the structural unit consisting of rolls and support member by means of a crane or the like, which necessarily presupposes the shutting down of the mill.
U.S. Pat. No. 5,035,131 discloses four rolling segments distributed symmetrically over the circumference of the support body of the rolling mill. In that mill, the chocks, the support body and cages holding the two sets of intermediate and work rolls must be removed from the roll stand after the end of the useful life of a rolling segment has been reached, for instance, after about 25 hours. The assembly is turned 90.degree. and reinstalled into the stand. This operation disadvantageously requires the shutting down of production.
In certain instances, rolling mills of the above mentioned type in which the useful life of the rolling segments is less than 25 hours. Such cases occur, for instance, upon the rolling of alloy steels having high resistance to deformation, or else upon the rolling of structural steels at low rolling temperatures, in which connection high reshaping resistances also result. If the rolling forces are, for instance, twice as great in this case, this means a reduction of the useful life of the rolling segments by a factor of eight.
To transport the sets of rolls out of the stand after about three hours in order to change the rolling segments, means an unacceptable interruption of production of at least about 30 to 40 minutes. Furthermore, there is the disadvantage that each set of heavy rolls can be turned only with difficulty and by means of heavy devices. For the depositing of the individual sets of rolls, a free space is required and the handling of the set of rolls ties up a heavy crane.